The present invention is directed to an improved envelope opener. In particular, the invention is directed to an improved shear station and peel back station for an envelope opener in which the edges of an envelope are sheared one edge at a time under control of a microcomputer.
Automatic envelope openers are known in the art. For example, see U.S. Pat. Nos. 3,590,548, 3,764,049, 3,875,722 and 3,822,523. Heretofore, high speed automatic envelope openers operated at fixed rates under control of relatively primitive electromechanical components. In certain envelope opening machines, three edges of the envelope had to be pre-weakened before the envelope could be opened and its contents exposed. In other machines, the edge of the envelope to be sheared was aligned for shearing by contacting one or more of the remaining envelope edges. This frequently resulted in misalignment of the envelope and, accordingly, incomplete severing of an envelope edge. In addition, such machines required cumbersome mechanism structure for guiding and aligning the envelope immediately prior to shearing.
In U.S. Pat. application Ser. No. 826,613, there is disclosed an envelope opening machine which can monitor the advance of an envelope through the machine. Such an envelope opening machine is fully automated and continuously operated under the control of a microcomputer. The envelope opening machine is capable of automatically indicating a jam condition and automatically shutting down under such condition. The present invention is directed to an improved shear station and peel back station for such a machine. The improved shear station includes a self-sharpening and self-aligning anvil assembly. The improved shear and peel back stations are able to transport overly thick envelopes which might otherwise cause a jam condition at the stations.